Separating apparatus for separating coarse material from fine material are known, in which a screening apparatus includes a frame and a pair of sloping vibratory shaker screens supported within the frame. Generally, the frame has a tall end and a short end joined by two sides, and has an angular funneling surface at the tall end directed downwardly toward the upper shaker screen. Soil or other solid particulate material to be screened into coarse material and finer material is dumped onto the upper shaker screen, for example, from the shovel of a front-end loader, and coarse material falls from the lower end of the upper shaker screen outside of the frame, while the material which is finer than the screen of the upper frame passes through the upper shaker screen to a lower vibratory screen of smaller opening dimensions which permits coarser material to be discharged at the one short end of the frame and finer material to pass through the lower shaker screen either onto a conveyor belt or be deposited within the frame for later retrieval.
Such separating apparatus may be portable and include at one end a towing means for a vehicle, and at the other end a set of wheels to provide transport of the apparatus to an operation site, and with the wheels moved relative to the frame between a road transport position and an operating position, generally with the frame on the ground. Such road-transportable vibratory loam and soil material screening apparatus are described in U.S. Pat. No. 4,197,194, issued Apr. 8, 1980; U.S. Pat. No. 4,237,000, issued Dec. 2, 1980; U.S. Pat. No. 4,256,572, issued Mar. 17, 1981; and Des. 263,836, issued Apr. 13, 1982, all hereby incorporated by reference, and which apparatus are known in the industry as Read SCREEN-ALL.RTM. soil separating apparatus (Read SCREEN-ALL.RTM. is the registered trademark of James L. Read, Middleboro, Mass.).
Generally, the pair of shaker screen assemblies in the above-described loam and soil material separating apparatus is secured on compression springs and the shaker assembly bounces on the springs in a rotary-type movement. Movement is imparted by the operation of an off-balance shaft mechanism secured to the upper and lower shaker mechanisms, generally by an off-balance flywheel secured to each end of a shaft, which shaft is driven by a hydraulic motor. Generally, the upper shaker screen is composed of a woven wire assembly of typically large diameter wire in order to withstand the impact of soil or another material dumped by a payloader directly onto the upper screen assembly, and which soil material may include large rocks or other heavy debris, while the screen of the lower shaker assembly is usually of a smaller diameter woven wire and having smaller openings selected for the particular separation desired.
While loam and soil material are generally quickly and efficiently separated in the above-described separating apparatus, where the feed material to the apparatus comprises a wide variety of material such as that found in landfills, which would include leaves, paper bags, sticks, as well as sand, soil, rocks, twigs, cans, bottles, domestic and industrial garbage and trash, and construction site debris, the separation of such material becomes more difficult.
There are a wide variety of vibratory screening apparatus employed to screen various, disparate feed-type materials, and which vibratory screening apparatus, rather than using woven wire screens, comprise comb or finger-like members composed of rods arranged in a series of decks over which the feed material is passed to be separated. The rod elements are downwardly sloping, overlapping, and spaced apart a defined distance to provide material separation. Typically, the screening decks are arranged in a shingle-array fashion or spaced apart, double shingle-array fashion, with each deck generally horizontally, or slightly downwardly tilted from the horizontal, and having a plurality or array of finger or rod-like members projecting from a transverse frame, so as to provide for the desired separation.
It is desirable to provide an improved separating apparatus and method, which apparatus remains road-transportable by vehicular transportation and which may be efficiently used by a variety of payloader vehicles, such as both front-end loaders and excavator-type payloaders to feed material to be separated onto the vibrating rod or screen separating surface.